George Entwistle, the former BBC director general, is expected to give evidence on Monday before Nick Pollard's inquiry into the handling of Newsnight's aborted investigation into sexual abuse by the late Jimmy Savile, in a demanding hearing that will see him grilled on what he knew about it by a silk.

The much criticised executive spent the last days of his short-lived director generalship preparing intensively for his appearance, which is expected to last several hours, and comes as the Pollard inquiry moves into its third week of evidence, having seen most of the senior BBC executives touched by the Savile film that never aired.

Those who have already appeared in front of Pollard, a former Sky News executive, include Newsnight's Jeremy Paxman and Kirsty Wark, as well as programme editor Peter Rippon, head of news Helen Boaden and her deputy Stephen Mitchell. Mitchell, one source said, gave eight hours of evidence.

The former director general, and the others, have had to submit hundreds of relevant emails, draw up a timeline of events and provide a summary statement, producing extensive documentation that required most to take external legal advice. They are then asked detailed questions by Maclean at the offices of law firm Reed Smith, which is organising the increasingly legalistic inquiry.

Entwistle, who was director of BBC Vision, responsible for the BBC's channels, at the time of the aborted Newsnight investigation, has said his only knowledge of the Savile film came from director of news, Helen Boaden, who briefly informed him over "a busy lunch" on 2 December of last year that if the Newsnight film aired "it may have an impact on your Christmas schedule". Entwistle said he did not have any role in the investigation being halted, telling MPs last month "I didn't want to show an undue interest" in matters outside his division.

However, he is likely to come under greater pressure over his handling of the Newsnight affair in the couple of months after the Savile allegations were first aired by ITV, and in particular will be questioned on why he relied for so long on the account of events provided by Newsnight's editor Peter Rippon, an account that had to be corrected at least three times. For instance, Rippon wrongly said that the police were aware of all Newsnight's unbroadcast material, when in fact one of the abuse victims filmed by the programme had never gone to the police.

Entwistle's severance agreement with the BBC – which saw him handed £450,000, or a year's pay, despite only lasting 54 days as director general – required him to give evidence to Pollard after he had left the BBC. Lord Patten, writing to John Whittingdale on the topic earlier this month, said that the payment, double the minimum for such a role, was needed to secure his "ongoing co-operation in a number of difficult and sensitive mattters".

Those giving evidence before Pollard have to sign a confidentiality agreement – although they are not being asked to give evidence on oath – at the legal hearings, where some have chosen to take their solicitors into to help them in what they have been told will be of an "inquistorial nature".

The BBC says that it will meet employees' legal costs – although there have been complaints that the broacaster is only making a contribution, and so leaving staff out of pocket. Entwistle's severance agreement gives him access to £10,000-worth of legal advice, according to Anthony Fry, a BBC trustee, who released the figure when giving evidence to parliament on Thursday morning.

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